Speaker magnet structure and method of forming the same



Dec. 14, 1965 E. A. HEPPNr-:R 3,222,753

SPEAKER MAGNET STRUCTURE AND METHOD OF FORMING THE SAME j Filed May 18,1959 Z @921% J/g' United States Patent 3,222,753 SPEAKER MAGNETSTRUQTURE AND METHD F FGRMHNG THE SAME Elmore A. Heppner, Round Lake,Ill., assigner to Heppner Manufacturing Co. Filed May 18, 1959, Ser. No.813,911 Claims. (Cl. 29-155.5)

This invention relates to magnet structures and in particular to magnetstructures for use in loudspeakers.

The principal feature of the invention is the provision of a new andimproved speaker magnet structure of simple and economical construction.

Another feature is the provision of such a speaker magnet structurewherein the magnet is retained in the housing by a new and improvedretainer.

A further feature of the invention is the provision of such a speakermagnet structure wherein the retainer provides an improved dustproofseal with the housing.

Still another feature of the invention is the provision of such aspeaker magnet structure wherein the secured relationship of theretainer with the speaker housing is effected by pressure exerted by theends of the retainer on the opposite housing walls.

A still further feature of the invention is the provision of a new andimproved method of forming such a speaker magnet structure.

A yet further feature is the provision of such a method of forming aspeaker magnet structure wherein the retainer is elongated in a novelmanner in the securing operation to provide the desired retainingpressure thereof on the opposite walls.

Other features and advantages of the invention will be apparent from thefollowing description taken in connection with the accompanying drawingwherein:

FIG. 1 is a side elevation of a speaker magnet structure embodying theinvention;

FIG. 2 is a diametric section thereof;

FIG, 3 is a vertical section thereof taken substantially along the line3 3 of FIG. 1;

FIG. 4 is a side elevation of a retainer in its original, unextendedconfiguration;

FIG. 5 is a side elevation of the retainer in the unextendedconfiguration and with a magnet shown in dotted lines secured therein;

FIG. 6 is a diametric section of another form of speaker magnetstructure embodying the invention; and

FIG. 7 is a side elevation of the retainer thereof in an unextendedconfiguration with the magnet secured therein.

In the exemplary embodiment of the invention, as disclosed in FIGS, 1through 5 of the drawing, a speaker magnet structure generallydesignated 11i is shown to comprise an open sided housing having a frontwall 12, a rear wall 13, a top wall 14 and a bottom wall 15. Front wall12 is provided centrally with a circular opening 16 adapted to receivethe speaker voice coil (not shown). Extending longitudinally betweenfront wall 12 and rear wall 13 coaxially of opening 16 is an annularretainer 17 in which is secured a permanent magnet 18.

Retainer 17 comprises an annular member formed of a non-magneticmaterial, such as a nonferrous metal, to preclude short circuiting ofthe magnetic field. The retainer may be formed by punch pressing or maybe machined, as desired. The rear portion 19 lof the retainer has anoriginal internal diameter smaller than the diameter of the rear portion20 of the magnet whereby magnet portion 2t) may have a press lit inretainer portion 19 and, thereby, be securely retained therein.

As best seen in FIG. 4, the retainer is provided with a front portion 21having a substantially larger diameter 3,222,753 Patented Dec. 14, 1965than rear portion 19 and joined to rear portion 19 by a generallytransversely outwardly extending, frustoconical portion 22. The forwardportion 23 of magnet 18 has a reduced diameter slightly smaller than thediameter of opening 16 to permit the concentric disposition of thespeaker voice coil (not shown) thereover. As 4best seen in FIG. 2, therear surface 24 of front wall 12 is provided with an annular groove 25concentrically surrounding opening 16 and receiving the forward end 26of retainer 17.

The method of forming speaker magnet structure 10 is as follows. Rearportion 19 of magnet 18 is forced into rear portion 19 of the retainer17, as shown in FIG. 5. As the over-all length of retainer 17 in theunextended configuration as seen in FIG. 5 is no greater than thespacing between front wall 12 and rear wall 13 of the housing 11, theassembled retainer and magnet may be positioned in the housing betweenwalls 12 and 13 in coaxial alignment with opening 16. A suitable gauge(not shown) may be employed to effect an accurate centering of themagnet relative to the opening.

A pair of semi-annular jaws 27 is now pressed against the exterior ofthe retainer at outwardly extending portion 22 to reduce the angularitythereof relative to the axis of the retainer and, thereby, effect anover-all elongation of the retainer. As a result of this elongation,front end 26 of the retainer seats in groove 25 to bear forcibly againstfront wall 12. The outer end 28 of the retainer is concurrently forcedagainst inner surface 29 of rear wall 13, whereby the retainer isforcibly secured between walls 12 and 13. Thus, magnet 18 is positivelyand accurately secured in coaxial relationship with opening 16.

Referring now to FIGS. 6 and 7, a modied form of speaker magnetstructure generally designated is shown to comprise a retainer 117generally similar to retainer 17 but having a rear portion 119 providedwith a diameter smaller than that of corresponding rear portion 19 ofretainer 17. Rear portion 119 has a press iit with a cylindrical magnet11S having a uniform diameter corresponding to the diameter of forwardportion 23 of magnet 18 and a length substantially equal to the spacingbetween the front surface 129 of a rear wall 113 and the front surface130 of a front wall 112 of a housing 111 similar to housing 11. Thus,the forward end 123 of magnet 118 projects forwardly of the front end126 of the retainer 117 to extend longitudinally through opening `116 ofthe front wall. Outwardly extending frusto-conica1 portion 122 ofretainer 117 is somewhat longer than corresponding portion 22 ofretainer 17 but functions similarly thereto in providing for an increasein the over-all length of the retainer upon a deformation which reducesthe agularity.

Magnet 118 is installed in retainer 117 subsequent to the disposition ofthe retainer between the housing walls, and preferably prior to theelongation lof the retainer. The installation of the magnet may bereadily effected by urging it through the opening 116 with the retainerdisposed coaxially behind the opening.

While I have shown and described certain embodiments of my invention, itis to be understood that it is capable of many modifications. Changes,therefore, in the construction and arrangement may be made withoutdeparting from the spirit and scope of the invention as dened in theappended claims.

I claim:

1. The method of securing a cylindrical speaker magnet between spa-cedwalls of a housing and coaxially of an opening in one of the walls,comprising the steps of: securing the magnet coaxially in an annularretainer provided with a transversely outwardly extending portion and anoriginal length substantially equal to the spacing between the walls;positioning the retainer coaxially of said opening with the oppositeends of the retainer juxtaposed to said walls; and deforming theoutwardly extending portion transversely inwardly toward alongitudinally extending configuration to increase the over-all lengthof the retainer and cause the ends to press retentively against saidwalls.

2. The method of securing a speaker magnet between spaced walls of ahousing, comprising the steps of: seccuring the magnet coaxially in anannular retainer provided with a transversely outwardly extendingportion and an original length substantially equal to the spacingbetween the walls; positioning the retainer with the opposite ends ofthe retainer juxtaposed to said walls; and deforming the outwardlyextending portion transversely inwardly toward a longitudinallyextending configuration to increase the over-all length of the retainerand thereby cause the ends to press retentively against said walls, andincrease the securing force of the retainer about the magnet.

3. The method of securing a speaker magnet between spaced walls of ahousing, comprising the steps of; forcing the magnet coaxially into apress tit with an annular retainer provided with a transverselyoutwardly extending portion and an orginal length substantially equal tothe spacing between the walls; positioning the retainer with theopposite ends of the retainer juxtaposed to said walls; and deformingthe outwardly extending portion transversely inwardly toward alongitudinally extending contiguration to increase the over-all lengthof the retainer and cause the ends to press retentively against saidwalls, and increase the securing force of the retainer about the magnet.

4. The method of securing a cylindrical speaker magnet between spacedwalls of a housing and coaxially of an opening in one of the walls,comprising the steps of positioning a retainer having a portionsubstantially conforming to the outer periphery of the magnet and havinga transversely outwardly extending portion and an original lengthsubstantially equal to the spacing between the walls coaxially of saidopening with the opposite ends Iof the retainer juxtaposed to saidwalls; locating a magnet in said retainer portion, and deforming theoutwardly extending portion transversely inwardly toward alongitudinally extending conguration to increase the 1overall length ofthe retainer and cause the ends to press retentively against said walls,and to secure the magnet coaxially in said retainer portion.

5. The method of securing an object between xedly spaced elements,comprising the steps of xedly associating the object with a deformablemember having a rst portion extending in one direction and an annularsecond portion extending laterally therefrom, disposing the member withsaid portions serially related between the elements, and turning thesecond portion substantially continuously circumferentially thereoftoward a configuration extending in said one direction to elongate themember in said one direction and cause the opposite ends thereofrespectively to engage securedly the spaced elements.

References Cited by the Examiner UNITED STATES PATENTS 1,058,210 4/1913Welch 29-522 1,561,872 11/1925 Lovejoy. 1,711,182 4/1930 Shrum.1,856,774 5/19312 Mayer 179-1155 1,941,477 1/1934 Jensen. 2,020,21211/1935 Quam 29-155.5 2,141,949 12/1938 Carbonneau 29-155.5 X 2,174,3559/1939 Sundstrom 179-1155 2,221,209 11/1940 Sims. 2,666,980 1/ 1954Russell 29-155.5 3,092,694 6/ 1963 Walczak 29-155.5 X

FOREIGN PATENTS 497,652 12/ 1950 Belgium.

389,898 3/1933 Great Britain.

397,617 8/1933 Great Britain.

WHITMORE A. WILTZ, Primary Examiner.

NEDWIN BERGER, JOHN F. CAMPBELL, Examiners.

1. THE METHOD OF SECURING A CYLINDRICAL SPEAKER MAGNET BETWEEN SPACEDWALLS OF A HOUSING AND COAXIALLY OF AN OPENING IN ONE OF THE WALLS,COMPRISING THE STEPS OF: SECURING THE MAGNET COAXIALLY IN AN ANNULARRETAINER PROVIDED WITH A TRANSVERSELY OUTWARDLY EXTENDING PORTION AND ANORIGINAL LENGTH SUBSTANTIALLY EQUAL TO THE SPACING BETWEEN THE WALLS;POSITIONING THE RETAINER COAXIALLY OF SAID OPENING WITH THE OPPOSITEENDS OF THE RETAINER JUXTAPOSED TO SAID WALLS; AND DEFORMING THEOUTWARDLY EX-